Modular System of an Axially Integrated Pump Structure

ABSTRACT

A modular system for a pump structure for the axial integration of a selection of electric drive assemblies (1) at a selection of pump assemblies (2) and a shaft bearing assembly (3) which includes a pump shaft (31) and a shaft bearing (32) with at least two rolling bearing sets, the shaft bearing (32) supporting the pump shaft (31) between a motor rotor (1) of the electric drive assembly (1) and a pump rotor (21) of the pump assembly (2) at a pump housing (20) of the pump assembly (2); wherein the selection of pump assemblies (2) jointly comprises a collar portion (23) at the pump housing (20) which accommodates the shaft bearing (32) in a through-hole of the pump housing (20) and protrudes to an accommodation side for an electric drive unit (1); and the selection of pump assemblies (2) differs with respect to the pump rotor (21) and/or a pump chamber (22); the selection of drive assemblies (1) jointly comprises a motor rotor (11) which is formed at a radially external section in the shape of a rotor cup (13), the rotor cup (13) radially encircling and axially intersecting the collar portion (23) that each pump housing (20) of the selection of drive assemblies (1) jointly comprises; and the selection of drive assemblies (1) differs with respect to a stator (12); and wherein for each combination of the selection of electric drive assemblies (1) and the selection of pump assemblies (2), at least one radial dimension of the pump shaft, the shaft bearing, the collar portion (23) and/or the rotor cup (13) are the same.

The present invention relates to a modular system for a compact pumpstructure for the axial integration of an electric drive assembly at apump assembly including a common shaft bearing.

An advantageous pump structure with a compact axial dimension is knowne.g. from patent application DE 10 2016 119 985 A1, which was not yetlaid-open on the application date of this patent application, by thesame applicant which describes a rotary piston vacuum pump. Said pumpstructure integrates the electric drive in a small installation spacewith the other components of the pump and has only a single shaftbearing with two ball bearing raceways. In comparison with a pumpstructure comprising two shaft bearings and an axially adjacentarrangement of the drive and pump, such a pump structure offers areduction in axial length and offers an advantageous basis for a pumpstructure of different pumps with a compact configuration and a smallaxial dimension. Furthermore, it is not necessary to take intoconsideration any centring tolerance between the bearing seats in thebearing clearances and assembly outlay with centring is not required forthe second shaft bearing. A reduced bearing clearance results in lesstilting of the shaft and thus in less wear of the shaft bearing.

Conventionally, in the case of the design of a pump structure, the pumptype and the use are initially determined, according to which adimensioning of components, such as a shaft bearing and a shaft seal, isdetermined on the basis of the forces and pressures occurring accordingto use. One form of the pump housing is designed individually ultimatelyfor the relative fixing and bearing of the assemblies around theselected components.

This gives rise to the circumstance that, in order to produce a productrange of different pumps which differ in terms of pump type, volumetricdesign or drive capacity, said approach requires for each pump anindividual pump structure having a large number of different components,in particular moulded parts, which always vary in dependence upon a typeof assembly or the parameters thereof. As a consequence, the productionof a product range consisting of different pumps is associated withconsiderable expense for providing a large selection of mould tools forcasting housing parts or for acquiring and stock holding the numerouscomponents and individual parts. Furthermore, different pump structuresamongst the products involve individual assembly sequences duringmanufacture. Accordingly, there is room for cost-reducingsimplifications in the production and assembly of different pumps from aproduct range.

It is an object of the invention to select common and different designfeatures between assemblies, which permits standardisation of the pumpstructure without impairing utilisation of the installation space. Inthe latter condition, the objective is particularly that of avoiding adeterioration in a compact configuration, as would exist e.g. byproviding a large universal installation space in the pump housing whichis used inefficiently in different embodiments.

This object is achieved in accordance with the invention by a modularsystem for a pump structure comprising the features of claim 1. Themodular system for a pump structure for the axial integration of anelectric drive assembly at a pump assembly includes: a selection ofelectric drive assemblies with different drive capacities; a selectionof pump assemblies with different volumetric capacities and/or differentconfigurations; and a shaft-bearing-assembly including a pump shaft anda shaft bearing with at least two rolling bearing sets, the shaftbearing supporting the pump shaft between a motor rotor of the electricdrive assembly and a pump rotor of the pump assembly at a pump housingof the pump assembly; the selection of pump assemblies jointly comprisesa collar portion at the pump housing which accommodates the shaftbearing in a through-hole of the pump housing and protrudes to anaccommodation side for an electric drive unit; and the selection of pumpassemblies differs with respect to the pump rotor and/or a pump chamber;the selection of drive assemblies jointly comprises a motor rotor whichis formed at a radially external section in the shape of a rotor cup,the rotor cup radially encircling and axially intersecting the collarportion that each pump housing of the selection of drive assembliesjointly comprises; and the selection of drive assemblies differs withrespect to a stator; and wherein for each combination of the selectionof electric drive assemblies and the selection of pump assemblies, atleast one radial dimension of the pump shaft, the shaft bearing, thecollar portion and/or the rotor cup are the same.

Therefore, the invention firstly provides a modular system which definesan axial intersection of the assemblies as a spatial interface betweenselection combinations amongst the assemblies in order to permit designstandardisation of the pump structure or the use of identicalcomponents. The modular system permits a universal integration of anindividual combination of assemblies out of a selection of assemblies ina compact pump structure. The standardisation of components and arelative arrangement thereof with respect to one another provides, inthe manufacture of pumps, cost advantages by reason of a reduction inthe production of different moulded parts and a reduction in differentprocedures and tools during the assembly of the pumps.

By virtue of the inventive specification of identical features anddistinguishing features or parameters within a selection of therespective assemblies, a spatial interface for standard components isfirstly selected between three assemblies in a pump structure. Thisstructural interface defines at the same time an axial intersection ofthe assemblies, whereby an integrated compact pump structure is achievedfor each combination of assemblies.

For example, by reason of a width of the stator of the electric drive adrive capacity can be increased by means of larger field coils, whereasall other components including the rotor cup remain the same. Likewise,a size of the pump rotor and the pump chamber can vary, whereas allother components and assemblies of the pump structure remain the same.Furthermore, a pump assembly of another pump type can be connected tothe same pump shaft, whereas all other components and assemblies of thepump structure remain the same.

Adopting a common radial dimension within the spatial interface ensuresnot only that the assemblies can be integrated in an axial intersectionbut also that identical components or components with identicaldimensions, such as e.g. an identical shaft bearing and a pump shaftconsisting of a blank with an identical diameter, can be used.

According to one aspect of the invention, for each combination out ofthe selection of electric drive assemblies and the selection of pumpassemblies, a collar portion with the same outer diameter can beprovided on the side of the pump housing and a rotor cup with the sameinner diameter can be provided on the side of the motor rotor.

By specifying the ratio of the diameter between the collar portion andthe rotor cup, a spaced interface can be defined between the componentsin the radial direction. This mutual radial spaced interval ispreferably selected to be small. A defined small spaced interval in thecase of each selection combination ensures optimum utilisation of theinstallation space in the pump housing and the objective of a universalyet compact pump structure is achieved.

Furthermore, said specification of the diameters renders it possible touse, for all electric drive assemblies, the same main body for the motorrotor. The rotor cup of the rotor needs merely to be adapted, whereappropriate, in terms of an axial length. Furthermore, the outerdiameter of the rotor cup of such an identical main body of the motorrotor for all electric drive assemblies can be adapted to a relevantstator of a respective electric drive assembly merely by means ofmodified provision and attachment of magnet bodies as rotor poles.

According to one aspect of the invention, for each combination out ofthe selection of electric drive assemblies and the selection of pumpassemblies, on the side of the pump housing, a collar portion with thesame inner diameter, the same shaft bearing and a pump shaft with thesame outer diameter can be provided.

This ensures that the same shaft bearing or a shaft bearing with thesame outer diameter can always be used for each selection combination ofthe assemblies, thus achieving optional standardisation of the modularsystem. Therefore, this also provides the possibility of using, fordifferent pump assemblies in combination with electric drive assembliesof the dry runner type, a similar or the same shaft seal which isarranged within the collar portion.

According to one aspect of the invention, for each combination out ofthe selection of electric drive assemblies and the selection of pumpassemblies, a motor chamber with the same inner circumference portioncan be formed in the pump housing.

By specifying an identical inner diameter and optionally a step portion,it is possible to provide, for all stator types out of the selection ofelectric drive assemblies, a fixing arrangement, whereby design andmanufacture of the pump housing, or at least a housing portion thereof,and assembly are simplified. On the other hand, an identical outercircumference of each stator yoke with respect to the pump housing canbe provided with a varying width in the axial direction.

According to one aspect of the invention, the motor chamber can beclosed to one axial side of the pump housing by a motor cover with anintegral pin-fin heat sink in which control electronics may beaccommodated for an electric drive assembly.

By means of the common feature of a cover for the motor chamber, auniform assembly sequence permitted when assembling the electric driveassemblies. A pin-fin cooler which can be integrated in each cover canbe the same, just like a universal accommodation at the inner side whichis suitable for bringing different control electronics of each electricdrive assembly into thermal contact. If the pump has a specified housingcircumference or a contour for accommodating the different stator typesof the electric drive assemblies, the entire cover for all or manyselection combinations of the assemblies can be the same component,wherein a feature of the pin-fin cooler is omitted for liquid-cooleddrives.

According to one aspect of the invention, at least one part of the pumphousing that includes the through-hole and the collar portion, and/orthe motor cover is made of a material suitable for impact extrusion,preferably cold impact extrusion.

Impact-extruded parts have, by reason of the provision method, a smallerformation of air bubbles and cavities as well as inclusions of foreignbodies and have better thermal and mechanical properties thanconventional die cast parts. A better thermal conductivity coefficienthas a particularly advantageous effect in a housing portion between theelectric drive assembly and the pump assembly because an improvedthermal transition of the electric power loss from the stator of theelectric drive assembly to the pump chamber can thus be achieved. In thepump chamber, the waste heat is rapidly dissipated by the mass flow ofthe conveyed medium. As a result, cooling of the stator is improved. Abetter thermal conductivity likewise has an advantageous effect in theregion of the cover of the motor chamber, wherein, in particular, animproved thermal transition of the control electronics via the pin-fincooler to the environment can be achieved.

A higher level of mechanical strength, in particular stiffness ofimpact-extruded bodies in comparison with a conventional die cast body,such as an aluminium die cast, also brings about advantages in theregion of the accommodation of the shaft bearing, i.e. the collarportion. In particular, in the case of displacement pumps, tiltingmoments occur at the pump shaft which are absorbed by the pump housingvia the shaft bearing. In comparison with a conventional die cast part,the collar portion can be designed for accommodating the shaft bearingin order to achieve a comparable level of mechanical stiffness with asmaller wall thickness. In turn, a smaller wall thickness in this andfurther housing portions saves material costs and weight.

The invention will be explained in greater detail hereinafter withreference to drawings relating to various embodiments arising fromvarious selection combinations out of the assemblies of the modularsystem. In the drawings:

FIG. 1 shows a water pump, of which the electric drive is configured asa dry runner;

FIG. 2 shows a water pump, of which the electric drive runs in aseparate cooling medium which is separate from the conveyed coolingwater;

FIG. 3 shows a slush/air pump, of which the electric drive is configuredas a dry runner;

FIG. 4 shows an oil pump, of which the electric drive is configured as adry runner;

FIG. 5 shows an oil pump, of which the electric drive is configured as awet runner; and

FIG. 6 shows a vacuum pump, of which the electric drive is configured asa dry runner.

FIG. 1 shows a first embodiment of a pump consisting of a modular systemin the form of a water pump, of which the electric drive is designed asa dry runner. The pump assembly 2 is a centrifugal pump of the radialpump type. On the right-hand side, the pump assembly 2 is only partiallyillustrated, wherein a pump cover has been removed which radiallysurrounds and axially delimits a pump chamber 22. In this embodiment,the pump rotor 21 is designed as a radial impeller 21 a and has acentral intake opening, through which a conveyor flow of a cooling wateris drawn in and accelerated radially into the pump chamber 20. Around anexit region of the radial impeller 21 a, a spiral housing portion, notillustrated, is provided in the pump cover, not illustrated, throughwhich the conveyor flow is tangentially discharged through a pumpoutlet. Such generally known details relating to the pump assembly 2 ofthe radial pump type are not stated further in order to reduce thelength of the disclosure.

A rear side of the pump chamber 22 behind the impeller 21 a is formed bythe illustrated part of a pump housing 20. The pump housing 20 has athrough-hole for a pump shaft 31 which is sealed with respect to thepump chamber 22 by means of a shaft seal 33. The pump shaft 31 extendsfrom the impeller 21 a through the through-hole of the pump housing 20to an electric drive assembly 1 and is mounted on the pump housing 20 bymeans of a single shaft bearing 32. The shaft bearing 32 has two rollingbearing sets with spherical rolling bodies in order to be able to absorbradial and axial forces and also tilting moments of the pump shaft 31within a single shaft bearing 32. The shaft bearing 32 is fitted into acollar portion 23 of the pump housing 20. The collar portion 23protrudes concentrically with respect to the through-hole of the pumphousing 20 to the side of the electric drive assembly 1.

The electric drive assembly 1 comprises a motor rotor 11 and a stator 12as well as control electronics 14. On the same side, the pump housing 20has a cylindrical outer wall which surrounds a motor chamber 10 foraccommodating the electric drive assembly 1. The outer housing wall ofthe pump housing 20 extends concentrically with respect to the collarportion 23 and so an annular volume for accommodating the stator 12 ofthe electric drive assembly 1 is provided in the motor chamber 10. Anouter circumferential edge of the stator 12 is in contact with a stepportion of an inner surface of the motor chamber 10 and is thus radiallyand axially fixed.

The motor rotor 11 is fixed on a free end of the pump shaft 31 whichprojects out of the collar portion 23. The motor rotor 11 has, at aradially outer portion, a rotor cup 13 which axially intersects thecollar portion 23 of the pump housing 20 and encircles same radiallyoutside. An axial dimension and position of the rotor cup 13 correspondsto a facing inner surface of the stator 12. The rotor cup 13 serves as amagnet carrier for the rotor poles. Therefore, a hollow cylinder whichcorresponds substantially to the outer diameter of the collar portion 23plus a spacing gap remains within the rotor cup 13.

The windings of the field coils of the stator 12 extend to the left andright of the stator yoke into the motor chamber 10. The pump housing 20is open on an axial side of the motor chamber 10. The opened side of thepump housing 20 is closed by means of a motor cover 24. The motor cover24 has, on an outer side, a multiplicity of parallel-protruding pins andforms a so-called pin-fin heat sink. On the inner side, the motor cover24 has a surface which is in thermal contact with control electronics 14of the electric drive assembly 1. In particular, the control electronics14 has electronic modules or power electronics, such as e.g. capacitorsand transistors, which are wired on a printed circuit board and theprinted circuit board is in surface contact with the accommodationsurface of the motor cover 24. Arranged between the pump housing 20 andthe motor cover 24 is a connector which is illustrated on the upperhousing side and guides lines to an electric power supply.

FIG. 2 shows a second embodiment of a pump of the modular system in theform of a coolant pump, of which the electric drive assembly is cooledwith the aid of a bath in a separate medium. The pump assembly 2corresponds substantially to that of the first embodiment and has,again, the radial impeller 21 a as the pump rotor 21. In the viewprovided in FIG. 2, a part of the pump housing 20 which surrounds thepump chamber 22 is not described further in order to reduce the lengthof the disclosure to the essential aspects of the invention.

On a rear side of the radial impeller 21 a, the pump housing 20 has apressure equalisation chamber 26, over the circumference of which apressure equalisation membrane 27 is tensioned. A rear side of thepressure equalisation chamber 26 is connected to the motor chamber 10via a bore. The motor chamber 10 is filled with a dielectric coolingmedium which is introduced into the pump housing 20 through a closableopening. The dielectric cooling medium surrounds the field coils of thestator 12 and discharges waste heat from the power loss of the statorvia the pump housing 20 to the environment and in particular to aconveyor flow in the pump chamber 22 of the pump assembly 2.

Pressure fluctuations which arise in the closed volume of the motorchamber 10 by reason of the temperature fluctuations in the electricdrive assembly 1 are transmitted by the pressure equalisation chamber 26via the pressure equalisation membrane 27 to the pump chamber 20 and soa pressure equilibrium is achieved between the motor chamber 10 and thepump chamber 22.

The first embodiment and the second embodiment have the same pump shaft31 and the shaft bearing 32. Furthermore, parts of the pump housing 20for accommodating the electric drive assembly 1, such as the collarportion 23 and an outer wall of the pump chamber 10, as well as themotor cover 24, correspond with one another. Likewise, an inner diameterof the rotor cup 13 on the motor rotor 11 corresponds to that of thepreceding embodiments.

FIG. 3 shows a first embodiment of a pump consisting of the modularsystem in the form of a slush pump or air pump, of which the electricdrive assembly is designed as a dry runner. The pump rotor 21 isdesigned as a peripheral wheel 21 b. The pump housing 20 forms anannular channel as a pump chamber 22 around the peripheral wheel 21 b. Apump inlet and a pump outlet are arranged adjacent one another on thecircumference of the annular channel of the pump chamber 22. This pumptype can convey liquid and also gaseous fluids as well as a mixture ofthe two phases and is used e.g. for a fuel cell.

In comparison with the preceding embodiments, the stator 12 of theelectric drive assembly 1 has a smaller drive capacity. The stator 12 ofthis embodiment has been configured in such a way that an axialdimension including the field coils has been reduced in comparison withthe preceding embodiments. However, parts of the pump housing 20 foraccommodating the electric drive assembly 1, such as the collar portion23 and an outer wall of the pump chamber 10, as well as the motor cover24, also correspond to those of the preceding embodiments. Likewise, aninner diameter of the rotor cup 13 on the motor rotor 11 corresponds tothat of the preceding embodiments. The shaft bearing 32 and a blank asan initial body of the pump shaft 31 are identical.

FIG. 4 shows a fourth embodiment of a pump consisting of the modularsystem in the form of an oil pump, of which the electric drive assembly1 is designed as a dry runner. A shaft seal 33 for sealing thedry-running drive assembly 1 is arranged behind the shaft bearing 32 inthe collar portion 23 and so the shaft bearing 32 is lubricated by theconveyed oil.

The pump assembly 2 is a displacement pump of the gerotor type. The pumprotor 21 is designed as a gerotor inner element 21 c, of which the outerrotor toothing is in meshing engagement with an inner rotor toothing ofa rotatable gerotor outer element 28. The pump cover 25 has a centralpump inlet. The pump outlet is not illustrated in this sectional view.Moreover, further details of the pump assembly 2 have not been describedfurther in order to reduce the length of the disclosure to essentialfeatures of the invention.

The electric drive assembly 1 of the fourth embodiment has a largerdrive capacity, in particular a high drive torque, corresponding to therequirement of a displacement pump, in comparison with the precedingembodiments. The stator 12 of the electric drive assembly 1 of thisembodiment has been configured in such a way that an axial dimensionincluding the field coils is longer in comparison with the precedingembodiments. Accordingly, a diameter of the field coils of the stator 12and an axial dimension of the magnetic poles on the rotor cup 13 arelarger than in the case of the preceding embodiments. However, an axialdimension of parts of the pump housing 20 for accommodating the electricdrive assembly 1, such as the collar portion 23 and an outer wall of thepump chamber 10, as well as the motor cover 24, also correspond to thoseof the preceding embodiments. Likewise, an inner diameter of the rotorcup 13 on the motor rotor 11 corresponds to that of the precedingembodiments. The shaft bearing 32 and a blank as an initial body of thepump shaft 31 are identical.

FIG. 5 shows a fifth embodiment of a pump consisting of the modularsystem in the form of an oil pump, of which the electric drive assembly1 is designed as a wet runner. The pump assembly 2, details of which arenot discussed further in order to reduce the length of the disclosureis, again, a gerotor pump comprising a gerotor inner element 21 c as thepump rotor 21 and a rotatable gerotor outer element 28 which correspondsubstantially to those of the fourth embodiment.

The drive capacity of the electric drive assembly 1 correspondssubstantially to that of the fourth embodiment, but it is not sealed bymeans of a shaft seal 33 and therefore is in contact with the conveyedoil. The motor cover 24 differs from the fourth embodiment in that itdelimits the control electronics 14 from the oil in the motor chamber10. In turn, the control electronics 14 can be covered with respect tothe outer side by a cover, not illustrated. The shaft bearing 32 and ablank as an initial body of the pump shaft 31 are identical.

FIG. 6 illustrates a sixth embodiment of a pump consisting of themodular system in the form of an oil-free, dry-running vacuum pump. Thepump assembly 2 consists of a rotary piston 29 which is moved in anoscillating manner in the pump chamber 22 and at the same time, on theone hand, draws in air through an inlet and, on the other hand,displaces air and pushes out same through pressure valves into anoutlet.

The rotary piston 29 is driven by means of a crank pin on a rotary plate21 d which engages into a long hole in the rotary piston 29. The pumprotor 21 of the sixth embodiment is thus designed as a rotary plate 21 dcomprising a crank pin.

The stator 12 of the electric drive assembly 1 in the sixth embodimenthas a smaller drive capacity in comparison with the fourth and fifthembodiment of an oil pump. The stator 12 of this embodiment has beenconfigured in such a way that an axial dimension including the fieldcoils has been reduced in comparison with the fourth and fifthembodiments. However, parts of the pump housing 20 for accommodating theelectric drive assembly 1, such as the collar portion 23 and an outerwall of the pump chamber 10, as well as the motor cover 24, alsocorrespond to those from preceding embodiments. Likewise, an innerdiameter of the rotor cup 13 on the motor rotor 11 corresponds to thatof the preceding embodiments. The shaft bearing 32 and a blank as aninitial body of the pump shaft 31 are identical.

A common aspect of all embodiments of the pumps consisting of themodular system is that the electric drive assembly 1, the pump housing20 of the pump assembly 2 and the shaft bearing assembly 3 are arrangedin an integrated manner in the pump structure such that they axiallyintersect one another. The same sequence of components of the assembliesis always provided in the radial direction from inside to outside,namely the pump shaft 31, the shaft bearing 32, the collar portion 23,the rotor cup 13, the stator 12 and an outer wall of the pump housing 20which defines the motor chamber 10.

Whether a shaft seal 33 is used and whether the shaft seal 33 isarranged in front of or behind the shaft bearing 32 can be varied bypositioning the shaft seal 33 in the standard collar portion 23 fordifferent types of electric drive assemblies 1, such as dry runners andwet runners, using assembly procedures without having to manufacturedifferent moulded parts for the pump housing. The shaft bearing 32 and apump shaft 31 or a blank thereof having the same diameter can beprovided in each pump from a selection combination of the assembliesconsisting of the same components.

In order to achieve the largest possible number of common components fora universal integration of individual selection combinations amongst theassemblies, a portion of the pump housing 20 which delimits the pumpchamber 22 and the motor chamber 10 and comprises the collar portion 23and a step portion, on the inner surface of which the stator 12 isaxially fixed, is designed having the same radial dimensions and ismanufactured as a standard impact-extruded part with or without thefeature of a pin-fin cooler. Likewise, the motor cover 24 is designedfor several embodiments having the same dimensions and is manufacturedas a standard impact-extruded part, wherein for liquid-cooled electricdrive assemblies 1 of the wet runner type an integrated pin-fin heatsink to the outer side can be omitted. Furthermore, the motor rotor 11comprising the rotor cup 13 having the same radial dimensions is formedat least prior to the provision of rotor poles with the same innerdiameter and is manufactured as a standard deep-drawn part or sinteredpart having good magnetic properties.

The adaptation to the electric drive assemblies 1 is thus effected bymeans of a length of the axial dimension of the pump housing 20 and therotor cup 13 and by providing the magnetic poles in dependence upon thefield coils of a selected stator 12. Moreover, a configuration of thepump assembly 2 in dependence upon the selected combination of the pumprotor 21 and pump chamber 22 in relation to the pump housing 20 isstandardised by implementing specific features, such as a pump inlet andpump outlet or a spiral housing, not on the side of the aforementionedstandard portion of the pump housing 20 but instead on the side of anindividual pump cover 25.

LIST OF REFERENCE SIGNS

1 electric drive assembly

2 pump assembly

3 shaft bearing assembly

10 motor chamber

11 motor rotor

12 stator

13 rotor cup

14 control electronics

20 pump housing

21 a radial impeller

21 b peripheral wheel

21 c gerotor inner element

21 d rotary plate with crank pin

22 pump chamber

23 collar portion

24 motor cover

25 pump cover

26 pressure equalisation chamber

27 pressure equalisation membrane

28 gerotor outer element

29 rotary piston

31 pump shaft

32 shaft bearing

33 shaft seal

1. A modular system for a pump structure for the axial integration of anelectric drive assembly at a pump assembly including: a selection ofelectric drive assemblies with different drive capacities; a selectionof pump assemblies with different volumetric capacities and/or differentconfigurations; and a shaft-bearing-assembly including a pump shaft anda shaft bearing with at least two rolling bearing sets, the shaftbearing supporting the pump shaft between a motor rotor of the electricdrive assembly and a pump rotor of the pump assembly at a pump housingof the pump assembly; wherein the selection of pump assemblies jointlycomprises a collar portion at the pump housing which accommodates theshaft bearing in a through-hole of the pump housing and protrudes to anaccommodation side for an electric drive unit; and the selection of pumpassemblies differs with respect to the pump rotor and/or a pump chamber;the selection of drive assemblies jointly comprises a motor rotor whichis formed at a radially external section in the shape of a rotor cup,the rotor cup radially encircling and axially intersecting the collarportion that each pump housing of the selection of drive assembliesjointly comprises; and the selection of drive assemblies differs withrespect to a stator; and wherein for each combination of the selectionof electric drive assemblies and the selection of pump assemblies, atleast one radial dimension of the pump shaft, the shaft bearing, thecollar portion and/or the rotor cup are the same.
 2. The modular systemaccording to claim 1, wherein for each combination out of the selectionof electric drive assemblies and the selection of the pump assemblies, acollar portion with the same outer diameter is provided on the side ofthe pump housing and a rotor cup with the same inner diameter isprovided on the side of the motor rotor.
 3. The modular system accordingto claim 1, wherein for each combination out of the selection ofelectric drive assemblies and the selection of the pump assemblies, onthe side of the pump housing, a collar portion with the same innerdiameter, the same shaft bearing and a pump shaft with the same outerdiameter are provided.
 4. The modular system according to claim 1,wherein for each combination out of the selection of electric driveassemblies and the selection of the pump assemblies, a motor chamberwith the same inner circumference is formed in the pump housing.
 5. Themodular system according to claim 4, wherein the motor chamber is closedto one axial side of the pump housing by a motor cover with an integralpin-fin heat sink in which control electronics may be accommodated foran electric drive assembly.
 6. The modular system according to claim 4,wherein at least one part of the pump housing that includes thethrough-hole and the collar portion, and/or the motor cover is made of amaterial suitable for impact extrusion, preferably cold impactextrusion.